WA State Dept of Ecology 9/18/2023

Joel Haack January 6, 2023 Page 14 Sources of Contamination: From 1894 to 1912, smelter operations resulted in the release of airborne particulate matter with high concentrations of arsenic and lead to the area surrounding the smelter.The Property is located approximately 0.5 miles west of the location of the former smelter. Shallow soil samples collected from LMGC indicated arsenic was present above the Method A cleanup level on the Property. Physiographic Setting: The Site is located within the Puget Sound Lowland Physiographic Province, a north-south trending structural and topographic depression that is bordered on its west side by the Olympic Mountains, and to the east by the Cascade Mountain foothills. The Puget Sound Lowland is underlain by Tertiary volcanic and sedimentary bedrock, and has been filled to the present-day land surface with Pleistocene-aged glacial and nonglacial sediments. The Property is located on the north end of the Everett Uplands, a north-south trending topographic high bounded on the east by the Snohomish River Valley and on the west by the Puget Sound.The ground surface at the Property is located at 80 feet above mean sea level (amsl) and is mostly flat. Surface/Storm Water System: Stormwater runoff on and in the vicinity of the Property disperses via sheet flow to catch basins connected to the City of Everett stormwater system. The nearest surface water body is Puget Sound, located approximately 2,000 feet east. Ecological Setting: The Site is zoned for low-density residential use. Adjoining properties to the north and west are also zoned for low-density residential use. Properties to the east and south are zoned as a park/open space. Surrounding properties to the north and west are mostly covered with impervious surfaces with some small landscaped areas.The Property is located adjacent to LMGC, which includes landscaped trees and open areas for golfing. A small pond is located immediately south of the Property. Geology: The geologic map of the area11 indicates that the Site is underlain by Vashon Till, a dense diamict with varying amounts of sand, silt, and gravel. The Property is underlain by fill materials placed to a maximum depth of 6.5 feet bgs. Fill materials are underlain by very stiff silt with sand to sandy silt, interpreted to be Vashon Till,to the maximum explored depth of 10 feet bgs. Groundwater: No monitoring wells are present on the Property. Groundwater has not been encountered in borings and excavations on the Property to the maximum explored depth of 10 li https://ngmdb.usgs.gov/Prodesc/proddesc_7476.htm